1. Field
The present invention relates to a privacy protection device, a privacy protection method, and a recording medium recorded with a privacy protection program, and more particularly, to a security technology for protecting privacy information from misuse by a browser that has browsed the content, the privacy information included in the content and related to the privacy of a provider.
2. Description of the Related Art
Recently, cell phones are becoming equipped with functions that enable not only phone calls, but also connecting to the Internet to browse websites as well as transmit and receive e-mail. Particularly, use of cell phones as Internet terminals has been rapidly increasing in recent years. Cell phones have functions such as digital camera functions, executive functions of application software, and GPS functions (see, for example, Japanese Patent Laid-Open No. 2004-328310 or Japanese Patent Laid-Open No. 2002-373200). For example, cell phones having digital camera functions can photograph not only still images, but also moving images.
In accordance with the widespread use of such cell phones, a user can, for example, photograph specific buildings, landscapes, people, and so forth with a cell phone. The user can then transmit the photographed still images or moving images to an acquaintance or other people by e-mail. The user can also register the photographed still images or moving images to a blog system that manages blogs, thereby posting the photographed still images or moving images on the users blog. In this way, in recent years, a user can easily and readily handle contents such as still images, moving images, and voices.
By way of example, assuming that a user has photographed a specific landscape with a cell phone, in general, the cell phone automatically inserts additional information to the photographed still image (content) upon photographing of the specific landscape. The additional information includes, for example, creator name information, created time information, created location information, image width information, image height information, information of resolution in the horizontal direction of image, and information of resolution in the vertical direction of image.
Assuming that the user has registered the photographed still image to a blog system, a browser can, for example, easily browse the additional information included in the still image when the browser browses the still image posted on the blog. Specifically, the browser can browse the additional information by pointing the mouse pointer on the still image and right-clicking the image to open the property.
FIG. 28 is a schematic view showing an example of the additional information of the content displayed on a browser terminal used by the browser. As shown in FIG. 28, the browser terminal displays additional information such as the creator's name “Ichiro Tanaka”, the creation date and time “2007.01.01. 09.12”, the creation location “3653.0322, N, 13797.3792, E”, image width “441 Pixels”, the image height “355 pixels”, though resolution in the horizontal direction “96 dpi”, the resolution in the vertical direction “96 dpi”, bit depth “24”, and the number of frames
In this way, the browser can easily browse the additional information included in the still image. Therefore, the browser can, for example, figure out other activities of the user (provider) who has provided the still image. For example, when the user uses a cell phone to photograph a plurality of landscapes in the travel destination and uses the cell phone to post the photographed plurality of still images on the user's blog, the browser can figure out the user's activities at the travel destination from the created date/time and the created location of the plurality of still images posted on the blog.
Furthermore, for example, when the user has posted the photographed still images on the user's blog in real time, the browser can figure out the current location of the user from the created date/time and created location of the still images posted on the blog. The browser can also identify the user from the creator name of the still images posted on the blog. The creator name information, the created time information, and the created location information are privacy information related to the privacy of the user. Therefore, a malicious browser who has browsed the privacy information may do harm to the user who has provided still images.
In order to solve such a problem, a method provided with a policy determination server in a system connected to the Internet (see, for example, Japanese Patent Laid-Open No. 2004-258872) is conventionally used as a method of controlling the disclosure of privacy information related to the privacy of a user. Specifically, policies describing the disclosure requirements and the like of the privacy information are stored in the policy determination server, and the system can control the disclosure of the privacy information in accordance with the policies stored in the policy determination server.